Director Steven Soderbergh does not get the credit he deserves in 2018, breaking out in 1989 with the Palme D'Or winning Sex, Lies and Videotape he went on to become the first director in sixty years to be nominated twice for Best Director in the same year at the 2000 Academy Awards for Erin Brockovich and Traffic, the latter winning him the accolade. Soderbergh returned from a filmmaking hiatus in 2017 with the excellent Logan Lucky, featuring the kind of star-studded cast and tongue-in-cheek wit he has perfected over the last thirty years. Showing no signs of slowing down, Soderbergh returns to his experimental roots with Unsane, a creepy, tense psychological thriller shot entirely on an iPhone, definitively proving that a great director doesn't need expensive equipment to produce an excellent film.

After fleeing to a foreign city to escape her stalker, Sawyer (Claire Foy) is held in a mental institution against her will. As cabin fever sets in, she is convinced her stalker has returned and must prove to the staff at the crooked institution that she is of sound mind. It is established early on that Sawyer is suffering from some form of post-traumatic stress, but it is not made immediately clear if this was caused by her stalker or just a fabrication of her supposed psychosis. The brilliance of Unsane is how long Soderbergh, with the aid of screenwriters Jonathan Bernstein and James Greer, keeps this mystery up – there is doubt in both the audience and Sawyer's own mind all the way until the final act, creating a lingering sense of tension throughout. A lot has been said about Soderbergh's decision to shoot entirely on an iPhone. Why is one of the most critically acclaimed directors of the modern era using such amateur equipment to shoot his films? Has he gone insane? Anyone who's seen Soderbergh's bizarre semi-real experimental comedy Schizopolis knows that the answer to this question is a definitive ‘yes', but that is beside the point. Modern iPhones shoot in 4K HD, so there is no noticeable difference in the quality of the picture. In fact, the limited functionality of the iPhone camera gives the cinematography an eerily omniscient feel which perfectly matches the tone of Unsane; just like the plot of the film, and Sawyer's own mind, everything feels just a little bit off. This film looks like nothing else, which only makes every skin-crawling twist feel that much more disturbing.

Claire Foy in ‘Unsane'.

Unsane comes in at a lean 98 minutes, allowing Soderbergh to maintain the mystery surrounding Sawyer's sanity for the majority of the film. Initially, the dialogue is lazy and expositional, introducing Sawyer as scatterbrained and volatile, supposedly as a result of her abusive relationship. Thankfully, once these half-baked introductions are out of the way, it is plain sailing; Unsane remains taught and unpredictable all the way up to its thrilling finale with Soderbergh using the iPhone's compact size and maneuverability to his advantage. While Soderbergh's 90s breakout peers Paul Thomas Anderson and Quentin Tarantino look to the past for their inspiration, Soderbergh has proven with both Logan Lucky and Unsane that he is making films rooted firmly in the modern day. Camera choice aside, Unsane acts as a takedown of toxic ‘nice guy' culture; Sawyer meets her stalker while he is grieving, and he interprets her sympathy as love, developing intense and unrequited feelings that eventually become obsession. Women in films are often portrayed as villains for not reciprocating the romantic feelings towards the men who do nice things for them. Unsane holds a mirror up to this behavior by showing the most extreme possible outcome, as well as commenting on the PTSD that survivors of abusive relationships are often left with.Unsane is horror in its purest form; unpredictable, off-kilter and grounded in a skin-crawling reality. By turning his budgetary limitations into an artistic decision, Soderbergh has proven once again that he is one of the most exciting and forward-thinking directors in the business. A committed performance from Claire Foy and a snappy run-time ensures that doubt over Sawyer's sanity are at the forefront of the audience's mind all the way through to its thrilling conclusion. If Soderbergh's post-hiatus output is anything to go by, his next project – a sports drama from Moonlight scribe Tarell Alvin McCraney – should be at the top of everybody's most-anticipated list.Unsane is out now.